9. Embedded programming¶
Our Homework this week:¶
Our assignment this week is to:
Group assignment:¶
- Compare the performance and development workflows for other architectures
- Document your work to the group work page and reflect on your individual page what you learned
Individual assignment:¶
- Read the datasheet for your microcontroller
- Use your programmer to program your board to do something
- Learning outcomes
- Identify relevant information in a microcontroller datasheet.
- Implement programming protocols.
Have you answered these questions?¶
- Linked to the group assignment page
- Documented what you learned from reading a microcontroller datasheet.
- Programmed your board
- Described the programming process/es you used
- Included your source code
- Included a short ‘hero video’ of your board
Reading the data sheet¶
While I have looked at many data sheets in the past in order to determine pin outs and other basic information about integrated circuits, I have never tried to read a significant portion of a data sheet. There is quite a lot that I don’t understand. I find it very helpful to have the table of contents open on the left in order to understand how each section relates to other sections of the data sheet.
What I have found most useful, is to skip around and to revisit sections of the data sheet after having read through other sections. For example the block diagram is a bit confusing and overwhelming initially. It begins to make a bit more sense after reading some of the other sections that touch on elements that are incorporated into the block diagram. Wow I wouldn’t go so far as to say that I understood the block diagram, I think it is fair to say that I at least recognize some of the different elements that are incorporated into it. For example you can see the ADC and DAC represented — these stand for analog to digital and digital to analog converter’s respectively.
The USART block connects to RX, TX, XCK, and XDIR. I know that RX and TX at least are on separate pins for receiving and transmitting data respectively.
https://ccrma.stanford.edu/wiki/Microcontroller_Architecture#:~:text=A%20microcontroller%20is%20essentially%20a,interfaces%20into%20a%20single%20chip.
Programming the Board¶
Code¶
I began by circling back to the example code we used to test my board previously. I started by just changing durations
/*
Blink
Turns an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
the correct LED pin independent of which board is used.
If you want to know what pin the on-board LED is connected to on your Arduino
model, check the Technical Specs of your board at:
https://www.arduino.cc/en/Main/Products
modified 8 May 2014
by Scott Fitzgerald
modified 2 Sep 2016
by Arturo Guadalupi
modified 8 Sep 2016
by Colby Newman
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink
*/
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(2, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level)
delay(500); // wait for a second
digitalWrite(2, LOW); // turn the LED off by making the voltage LOW
delay(2000); // wait for a second
}
Next, I decided to try to get both LEDs blinking. I starting with different durations in sequence ``` /* Blink
Turns an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to the correct LED pin independent of which board is used. If you want to know what pin the on-board LED is connected to on your Arduino model, check the Technical Specs of your board at: https://www.arduino.cc/en/Main/Products
modified 8 May 2014 by Scott Fitzgerald modified 2 Sep 2016 by Arturo Guadalupi modified 8 Sep 2016 by Colby Newman
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink */
// the setup function runs once when you press reset or power the board void setup() { // initialize digital pin LED_BUILTIN as an output. pinMode(2, OUTPUT); pinMode(4, OUTPUT); }
// the loop function runs over and over again forever void loop() { digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level) delay(1000); // wait for a second digitalWrite(2, LOW); // turn the LED off by making the voltage LOW delay(500); // wait for a second
digitalWrite(4, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second digitalWrite(4, LOW); // turn the LED off by making the voltage LOW delay(500); // wait for a second
} ``` Then had them blinking simultaneously:
``` /* Blink
Turns an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to the correct LED pin independent of which board is used. If you want to know what pin the on-board LED is connected to on your Arduino model, check the Technical Specs of your board at: https://www.arduino.cc/en/Main/Products
modified 8 May 2014 by Scott Fitzgerald modified 2 Sep 2016 by Arturo Guadalupi modified 8 Sep 2016 by Colby Newman
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink */
// the setup function runs once when you press reset or power the board void setup() { // initialize digital pin LED_BUILTIN as an output. pinMode(2, OUTPUT); pinMode(4, OUTPUT); }
// the loop function runs over and over again forever
void loop() {
digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level)
digitalWrite(4, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(4, LOW); // turn the LED off by making the voltage LOW
digitalWrite(2, LOW); // turn the LED off by making the voltage LOW
delay(500); // wait for a second
}
Next, I tried the button arduino example:
/* Button
Turns on and off a light emitting diode(LED) connected to digital pin 13, when pressing a pushbutton attached to pin 2.
The circuit: - LED attached from pin 13 to ground through 220 ohm resistor - pushbutton attached to pin 2 from +5V - 10K resistor attached to pin 2 from ground
- Note: on most Arduinos there is already an LED on the board attached to pin 13.
created 2005 by DojoDave http://www.0j0.org modified 30 Aug 2011 by Tom Igoe
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/Button */
// constants won’t change. They’re used here to set pin numbers: const int buttonPin = 3; // the number of the pushbutton pin const int ledPin = 2; // the number of the LED pin
// variables will change: int buttonState = 0; // variable for reading the pushbutton status
void setup() { // initialize the LED pin as an output: pinMode(ledPin, OUTPUT); // initialize the pushbutton pin as an input: pinMode(buttonPin, INPUT); }
void loop() { // read the state of the pushbutton value: buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed. If it is, the buttonState is HIGH: if (buttonState == HIGH) { // turn LED on: digitalWrite(ledPin, HIGH); } else { // turn LED off: digitalWrite(ledPin, LOW); } }
This actually functioned in reverse, which tells me that my button state is normally high.I swapped the LED highs and lows to be certain:
/* Button
Turns on and off a light emitting diode(LED) connected to digital pin 13, when pressing a pushbutton attached to pin 2.
The circuit: - LED attached from pin 13 to ground through 220 ohm resistor - pushbutton attached to pin 2 from +5V - 10K resistor attached to pin 2 from ground
- Note: on most Arduinos there is already an LED on the board attached to pin 13.
created 2005 by DojoDave http://www.0j0.org modified 30 Aug 2011 by Tom Igoe
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/Button */
// constants won’t change. They’re used here to set pin numbers: const int buttonPin = 3; // the number of the pushbutton pin const int ledPin = 2; // the number of the LED pin
// variables will change: int buttonState = 0; // variable for reading the pushbutton status
void setup() { // initialize the LED pin as an output: pinMode(ledPin, OUTPUT); // initialize the pushbutton pin as an input: pinMode(buttonPin, INPUT); }
void loop() { // read the state of the pushbutton value: buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed. If it is, the buttonState is HIGH: if (buttonState == HIGH) { // turn LED on: digitalWrite(ledPin, LOW); } else { // turn LED off: digitalWrite(ledPin, HIGH); } }
...and indeed, this worked as expected, if with some latency.
Next I wrote my own version combining the two examples:
```
const int led1 = 2; // the number of the LED pin #1
const int button = 3; // the number of the button pin
const int led2 = 4; // the number of the LED pin #2
int buttonState = 0;
void setup() {
//setting up pin modes
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(button, INPUT);
}
void loop() {
// put your main code here, to run repeatedly:
buttonState = digitalRead(button);
if (buttonState == HIGH) {
digitalWrite(led1, HIGH); // turn the LED on (HIGH is the voltage level)
digitalWrite(led2, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led2, LOW); // turn the LED off by making the voltage LOW
digitalWrite(led1, LOW); // turn the LED off by making the voltage LOW
delay(500);
} else {
digitalWrite(led1, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led1, LOW); // turn the LED off by making the voltage LOW
delay(500); // wait for a second
digitalWrite(led2, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led2, LOW); // turn the LED off by making the voltage LOW
delay(500);
}
}
Lastly, I wanted to experiment with adjusting the output based on different numbers of button presses. This tutorial was very helpful: https://www.circuitgeeks.com/arduino-push-button-tutorial/. To count button presses, you have to check whether the last state is different from the current state.
I tried this example from the site, modified for my board:
``` int ledPin[2] = {2, 4};
const int buttonPin = 3; int buttonState = HIGH; int pushCounter = 0; int numberOfLED = 2; void setup() { pinMode(buttonPin, INPUT); for (int i = 0; i <= 2; i++) { pinMode(ledPin[i], OUTPUT); } }
void loop() { buttonState = digitalRead(buttonPin); if (buttonState == LOW) { for (int i = 0; i < numberOfLED; i++) { if (pushCounter % numberOfLED == i) { digitalWrite(ledPin[i], HIGH); } else { digitalWrite(ledPin[i], LOW); } } pushCounter++; delay(400); } }
And got alternating blinking LEDs on a press which wasn't what I expected. I decided to try out serial communication to see if I was actually getting the expected data. Unfortunately, serial communication did not appear to be working at all.
const int buttonPin = 3; int currentState; // variable for reading the pushbutton status int pushCounter = 0; // counter for the number of button presses int lastState = HIGH; // previous state of the button
void setup() { Serial.begin(115200); Serial.println(“Push Button Counter”); Serial.println(” “); pinMode(buttonPin, INPUT); }
void loop() { currentState = digitalRead(buttonPin); if (currentState != lastState) { if (currentState == LOW) { pushCounter++; Serial.print(“Button Press Count = “); Serial.println(pushCounter); } } lastState = currentState; if (pushCounter >= 10) { Serial.println(” “); Serial.println(“Resettng the Counter…”); pushCounter = 0; } delay(50); }
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## Code Example
Use the three backticks to separate code.
// the setup function runs once when you press reset or power the board void setup() { // initialize digital pin LED_BUILTIN as an output. pinMode(LED_BUILTIN, OUTPUT); }
// the loop function runs over and over again forever void loop() { digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level) delay(1000); // wait for a second digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW delay(1000); // wait for a second } ```
Gallery¶
Video¶
From Vimeo¶
Sound Waves from George Gally (Radarboy) on Vimeo.